Video coding with a variable block-sizing technique in the wavelet transform domain

In this paper, we present an efficient video coding technique based on a va riable block-sizing (VBS) technique and the wavelet transform. Quadtrees ar e used for VBS segmentation on the wavelet-transformed frame which is decom posed into pyramid multiresolution subbands. Feature areas are extracted du ring the growth of the quadtree on each subband. Motion estimation/compensa tion and vector quantization are performed on only the extracted feature ar eas in the subband. Since the VBS technique is very effective in lowering o verall coding rates, the proposed coder is designed for very low bit-rate v ideo coding. Simulation results are presented at 14.4 kbits/s for videoconf erencing sequences. To evaluate the performance of the proposed coder, comp arisons are made with results obtained by the H.263 standard (C) 1998 SPIE and IS&T. [S1017-9909(98)01003-4].